CA2435505C

CA2435505C - Rac cooling

Info

Publication number: CA2435505C
Application number: CA 2435505
Authority: CA
Inventors: Rafic Adel Chehouri
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-07-07
Filing date: 2003-07-07
Publication date: 2004-10-26
Anticipated expiration: 2023-07-07
Also published as: WO2005004179A1; CA2435505A1; AU2003304302A1

Abstract

Method of cooling oil immersed transformer or an electrical machine by heat transfer to a liquefied gas, e.g. Freon. A first heat exchanger transfers heat from oil to liquefied gas, which circulates in a closed heat pump circuit with an evaporating cycle. Finally heat is removed by airflow. This done by either using external or remotely cooler unit containing heat exchanger in communication with conventional refrigeration unit on trailer or any fixed or movable applicable method to locate near Transformer, or by directly locating the heat exchanger and/or pre-engineered evaporating coil within the transformer housing connected to outside refrigeration unit. My new Transformer Oil cooler unit can be applied to existing transformers or can be adopted in new design and manufacturing of electrical Transformers, which can have better temperature control, and better cooling for the hot spot area in Transformers. This is a practical and cost effective system to cool electrical Transformers particularly under extreme conditions in which it will boost the transformers output and enhanced its efficiency. My system has not been previously available.
My invention is liquid (Oil) -to-Gas cooling method and not to be confused with current Liquid-to-liquid or any Gas-to-Gas cooling practice.

Description

Description BACKGROUND OF THE INVENTION
[~Ol ] 1. Field of the invention [0002] The invention pertains to cooling systems by Liquid (Oil) to Gas circulation method and refrigeration base of discussion for liquid (Oil) cooled electrical Transformer and other applicable equipments.

[0003] 2. Description of the related Art.

[0004] In case of Electrical Transformer, large electrical Transformer commonly use a liquid coolant, usually Oil, to dissipate un favourable heat rise within the transformer housing during the operation of the transformer and sometimes from outside weather condition. The coolant Oil may substantially fill the transformer housing and in most cases the liquid coolant action done by the thermodynamic law of convection. Most today transformer may contain different shape of design to define surface area to increase heat dissipation to the atmosphere, mostly like radiator type. But when the transformer operate at maximum in some and/ or additional heat rise impose on transformer from outside weather specially during summer time, the temperature of the liquid coolant may reach to undesirable temperature level, which threaten the transformer' operation and its life. Also the efficiency of the transformer goes lower. Additional cooling system for liquid coolant has been around the industry for quit some time.
Most today practices around the world are done by Forced Air, Forced Oil, or forced water separately of jointly. However, The cost and size of these systems and iig equipments are not cost effective and some time they are limited in efficiency under extreme condition operation. This is why my invention RAC COOLING is the most efficient system to practice in today and future, not only is cost effective, but best because is simple to adopt and will save great deal of energy loses and extend the life of very costly Transformers around Stations and substations worldwide and more. With RAC COOLING invention new era of Transformer cooling technology has been born and available. My invention is liquid (Oil)-to-Gas cooling not to be confused by any current liquid-to-liquid or Gas-to-Gas cooling practice.
OBJECT OF THE INVENTION

[0005] The object of this invention is to provide a better cooling system and method utilizing the conventional refrigerant cooling unit and practices used for lowering liquid (Oil) coolant temperature. The simplicity of RAC COOLING
Invention will allow providing better cooling practice to any exiting electrical transformer and can be done fixed to the transformer body or removable and portable application and rapidly transported to location needed with refrigeration unit quickly connected.

[0006) Another objective of this invention is to provide a cooling system and method for liquid cool electrical transformer when designed and build with minor modification to transformer housing. This will pave the way to smaller in size transformer based on new power delivery setting based on new temperature rise sefifiing of Electrical transformers.
2~g SUMMARY OF THE INVENTION

[0007] The concepts of the invention could be practiced on wide range of Liquid coolants. While most of electrical operated transformer has Oil coolant, the Oil is in contact with transformers Coifs; the Oil coolant absorbs the temperature rising from the heat generated within the transformer from transformer operation and from maybe additional outside heat imposed on transformer in hot weathered area and from any heat waves that suppresses the design criteria of the transformer. As said before, many design of transformer being practiced to increase the size of the coolant circulation and heat dissipation by coolant convection circulation and some time additional pipe opining is available to dissipate the extra heat to atmosphere. Forced Oil. Forced Air, and/or Forced water in additional to pumps and other equipments in many cases are being practiced to aid the cooling of the transformer. Best of today available based on heat exchange Liquid-to-liquid methods, but it is costly and not practical in many cases. Also my invention not to be confused with any current practice of Gas -to-Gas cooling for transformer with SF6 gas.
[0~8] With RAC COOLING invention practice, the transformer coolant is exposed to heat removing abilities of a heat exchanger, what I call Cooling Tank also, Where Both Oil and Gas circulate and the liquid receives coolant from conventional refrigeration unit where Gas being circulated and compressed.
The expansion coil or radiator is located within the cooling tank or what said heat exchanger where Oil liquid is circulating. The refrigerant will absorbed the heat in large quantity and dissipated to atmosphere through the refrigervtion cycle. It is way more effective and more efficient than coolant circulation and exposition to ambient temperature. Most fans re circulate hot air and not much effective because air losses density when heat rise. RAC COOLING invention permits coolants to be effectively cooled even under high ambient atmosphere temperatures.
[0009j The cooling Tank or as referred to also as heat exchanger may be either located along with the refrigeration unit adjacent to the transformer or the heat exchanger be located within the transformer housing connected to the outside refrigeration unit. If desired cooling Tank not needed, cooling area would be better representation where liquid cooling circulation taking place while oil circulation is happening by convection refrigerant in its circulation from refrigeration cycle. In case Heat exchanger located outside the Transformer, minimal modification to transformer housing required. Mostly connect conduit mostly the inlet and outlet for Oil circulation. While In case if Cooling Tank desired to be within the Transformer housing, modification required to host the new unit or additional items, again is not substantial it is simple to adopt.
[001 Oj RAC COOLING invention allows engineer and technician around the word to design and built their transformer cooler unit as they desire and as they see fit for their applications, this is additional flexibility offered with RAC
COOLING
invention. For already existing transformer a portable unit on back of truck or trailer or any other movable equipment. With using quick-connect couplings and flexible hoses may be connected fast to transformer inlets and outlets. Single refrigerant unit could be used to cool down multiple transformers, or alternate between transformers as situation required.
[001 1 j With RAC COOLING Invention little engineering work required as the heat exchanger unit and the refrigeration unit is conventionally constructed. Even with build in heat exchanger within the transformer, no major design changes required when adoption to the new system with currently design practices available with skilled personal in transformer manufacturing industries or related fields.
BRIF DESCRIPTION OF THE DRAWINGS
[0012] FIG.I is a schematic view of the embodiment of the invention, which can be described as block diagram presenting the invention system process.
[0013] FIG.2 is a schematic view of an embodiment of the invention wherein the heat exchanger or as described cooling tank is located outside the transformer housing.
[0014] FiG.3 is a schematic view the embodiment of the invention, wherein the heat exchange area or cooling area or media is within the transformer housing.
[0015] FIG.4 is a schematic view the embodiment of the invention wherein the heat exchanger and the refrigeration unit shown mounted on portable trailer or moving equipment.
DESCRIPTION OF THE PREFERED EMBODIMENTS
[0016] The file of this patent contains at least 4 drawings. More drawing would be added and amended as required. The patent office to contain all drawings in colour or black and Wight, and would be available upon request and necessary fees paid. While this invention is susceptible of embodiment in many different sis forms, there is shown in drawings and will herein be described in detail preferred embodiment Of the invention with the understanding that the present discloser is to be considered as an exemplification of the principles of the invention and is not intend to limit the broad aspect of the invention to the embodiments illustrated. The aforementioned objects and advantage of the invention will be appreciated more from the following description and accompanying drawings wherein:
[0017] FIG. 1 Is a block diagram viewing all base items relate to and application of RAC COOLING invention. The Transformer 1 or as said other equipment contain Oil or other substance, Liquid Oil pump 2 and/or any accessories related, Cooling tank 3 or as mentioned also heat exchanger unit, Refrigeration cycle 4 or as described conventional refrigeration unit with all related accessories, Oil 5 or as said first substance or liquid coolant, Gas 6 or as said refrigerant Gas and/or as said second substance in circulation within heat exchanger, Evaporating Coil 7 or as said other description Finn Radiator or similar item, Control panel 8 and/or and additional control to complete the operation of the said system such as temperature sensor, pressure gauges, flow meters etc... including locale or any remote control, Unit structure 9 or any preferred method to build and adopt the invention in its application including fixed , build within or portable shape and application.
[0018] FIG. 2 Is a schematic view of the embodiment of the invention wherein the cooling tank or said heat exchanger is located externally of the Transformer having liquid coolant. The Refrigeration unit is illustrated at 44 and is communicating with the cooling Tank 46. The Transformer 48 is connected by a conduit system 50 with the heat exchanger 46; the conduit 58 contains the coolant returning system adjacent the inlet and outlet ports of the heat exchanger. Arrows on FIG 4 indicate the direction of coolant. The pump 51 and valves 52-1,52-O and Quick-disconnect coupling if desired 54-I and 54-O may be incorporated into the heat exchanger unit, as may be the case with the embodiment of FIG.4, and it will appreciate that the operation of system of FIG.4 is identical to the operation of the apparatus shown in FIG.2. The transformer inlet and outlet valves with Quick-disconnect coupling are being identified in this drawing as 57-1,57-0,56-I and 56-O.
[0019] FIG.3 is another embodiment of RAC COOLING Invention schematically show the transformer 64 being constructed to house and adopt the heat exchanger unit or as said cooling area or cooling panels 66. It is relatively simple modification with today skilled transformer manufacturer and personal that work in this field. The heat exchanger part will absorb the heat and suck it to outside the transformer with the circulation and refrigeration unit 62 adopted outside the transformer. 71, 72, 73, 74, 76 and 78 are accessories related to complete safe operational refrigeration cycle or system, such as but not limited to valves, refrigeration conduits, etc... In this practice the new cooling method and system could do without pump and additional valves if desired or as per engineering designer see fit and cost effective, because the liquid coolant will be circulated through the convection from heat rise within the Transformer housing.
[0020] FIG. 4 in this schematic The said portable new Transformer cooler unit as I
have given number RAC-TC-A shown in better explanation but not limited to this design, it is to be understood clearly that many portable cooler unit based on the embodiment of RAC COOLING invention may be used and applied. The cooling tank or as said heat exchanger unit 28 show the evaporating coil or as vs said Finn radiator to cool and lower the temperature of the liquid coolant being circulated in conduits system 40 and 42. Arrows shows the flow direction. The inlet of cooling tank 34-1 show connected to outlet of transformer 20 as given number 36-O. The inlet of transformer 36-I is showing connected to outlet of heat exchanger 28 through 34-O. Pump 35 show in fine with Liquid coolant circulation, pump 35 may be in inlet side or outlet side of heat exchanger unit. The conventional refrigeration unit 26 is show in connection to heat exchanger unit 28. Control panel 25 show in communication with temperature sensor and any additional desired control items locally or remotely. Grounding 27 for safety of personal and equipment show in schematic. Item 24 is trailer, back of truck or even applicable wheel barrel or any applicable movable structure to adopt all said items per said embodiments may be used. One cooler unit could be used to cool more than one transformer.
[0021 ] While the specific disclosed embodiments have been illustrated and described, numerous modifications come to mind and may be apparent to those skilled in the art without departing from the sprit and scope of the invention. From above description also to be underlined and understood that singular can be referred to as plural, feminine as masculine and items described are not limited to any shape, made, material, size, type, number or colour and can be found and used from already existing conventional materials available in market or new designed and/or manufactured items to fulfill the sprit of the invention.

Claims

1. A Process and method for cooling oil or liquid coolant for electrical equipments using liquid to gas transfer application function comprising: a heat exchanger housing with inlet and outlets for oil circulation; a oil circulation pump for circulating the oil; a heat exchanger unit for liquid to gas heat transfer function by liquid to gas circulation; a heat pump with fan assembly; a conventional refrigeration and heat exchanging unit for heat exchange between the oil and the gas; an evaporator coil for completing the refrigeration cycle; a control panel for controlling the RAC (Rafic AC) cooling system; cooling system includes cooling oil immersed transformer or an electrical machine by pumping oil from electrical equipment to the heat exchanger and transferring heat from oil to liquid gas circulating in a closed heat pump cycle with an evaporating cycle for reducing the temperature of oil.

2. The process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 1 comprises a cooling unit that is remotely controlled.

3. A Process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 1 comprises a cooling unit which is integral to the electrical equipment.

4. A Process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 1 comprises a cooling substance which is Freon, Helium, Hydrogen or any other refrigerant gas.

5. A Process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 1 comprises cooling of oil or any other dielectric substance.

6. A Process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 1 comprises inlets and outlets equipped with quick connect couplings.

7. A Process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 6 comprising inlets and outlets equipped with quick connect couplings, which are manually or electrically operated.

8. The process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 1 where the cooling pump is a single or three phase pump.

9. The process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 1 comprises the heat exchanger housing with a drainage system.

10. The process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 1 comprises the control panel for controlling the refrigeration cycle, which is local or remotely controlled.

11. The process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 10 , the control panel comprises a sensor for measuring and controlling the oil temperature.

12. The process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 10 , comprises a evaporator coil made from a conventional finned radiator or any applicable type coil.

13. The process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 1 or 2, the cooling unit comprises a compressor of any applicable design.

14. The process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per claim 1 or 2, the heat pump comprising a condenser unit and a fan assembly of any applicable design.

15. The process and method for cooling oil for electrical equipments using liquid to gas transfer application function as per anyone of claims 1 to 14, the RAC cooling system can be mounted on a trailer or any moveable structure.